Connecting element with thread on both sides

ABSTRACT

Both threads of a connecting element--with thread on both sides for a detachable connection of two component parts or objects--consisting of several, preferably three joinable parts, i.e. base screw, secondary screw, and clamping nut, are right-handed.

The present invention relates to a connecting element with thread onboth sides for a detachable connection of two component parts or objectsaccording to the preamble of claim 1.

Connecting elements have been known which in their center show a screwnut and at the two opposite ends each comprise a thread. Theseconnecting elements have been constructed from one pierce for example byforging. The special characteristic of these connecting elements is thatone thread is right-handed, however the other thread is left-handed bywhich according to the turn direction of the nut two component parts orobjects connected by thread bottom hole borings and the two threads ofthe connecting element either withdraw from each other or approach eachother. A very particular characteristic of these connecting elements isthat by the latter a defined distance between the two component parts orobjects can be adjusted.

Furthermore it has been known that these connecting elements consist ofone piece because of which a possible alignment of the two componentparts or objects cannot be compensated.

Moreover, when assembling these known connecting elements for adetachable connection of the two component parts or objects there willarise further problems. To screw the connecting element into bothcomponent parts or objects at the same time these two component parts orobjects must be arranged in an initial distance which is at least aslong as the length of the connecting element. This is impossible athardly accessible places or considerably restricts the serviceability ofsuch a connecting element. Furthermore, when assembling the twocomponent parts or objects they must additionally be aligned with eachother in an exact manner because of the rigid one-piece construction ofthe connecting element.

Therefore it is the object of the present invention to avoid theabove-mentioned disadvantages of a detachable connection of twocomponent parts or objects and particularly to create a connectingelement which can be used at hardly accessible places and is constructedin a simple and robust manner and easily to be handled.

This object is solved by means of a connecting element consisting ofseveral joinable parts the two thread parts of which are right- as wellas left-handed according to the characteristics described in thecharacterizing clause of claim 1 of the corresponding patent claims. Thepresent invention allows a considerable reduction of the assembly timeand thereby of the expenses of assembling. Furthermore, when renouncingthe passage borings also these elements can be connected to each otherwhich otherwise are not accessible from any side or are only hardlyaccessible and/or, because of restricted space conditions, areaccessible in a complicated manner only.

In the following there will be described a preferred embodiment of theinvented connecting element with the help of the enclosed drawings.

In these drawing the figures show the following:

FIG. 1: The cross-section of the connecting element in assemblycondition with the two component parts or objects,

FIG. 2: A lateral view and a cross-section of the joined connectingelement,

FIG. 3: The construction of the base screw in side view and incross-section the construction of the secondary screw,

FIG. 4: Plan view and cross-section of the clamping nut,

FIG. 5: As lateral view different dimensions of the base thread of thebase screw,

FIG. 6: Plan view and lateral view of various designs of the clampingnut.

The connecting element (1) in FIG. 1 serves for detachable connection oftwo objects or component parts (2, 3), particularly for connecting twoobjects (2, 3) at places inaccessible or only hardly accessible by oneor both object sides, e.g., walls erected to separate rooms.

FIG. 2 shows the inner and exterior composition of the preferredembodiment of the connecting element (1) consisting of the threecomponents base screw (4), secondary screw (5), and clamping nut (6) inassembled condition.

The base screw (4) shown in FIG. 3 comprises a right-handed base thread(7) and a joining cap screw (8) the latter (8) consisting of a stop (9),a distance section (10), and a locking section (11) with truncated conein its preferred embodiment provided with a recess (12) at its frontside for the reception of a screw turning device not shown here, e.g. ascrewdriver. This recess (12) is in the preferred embodiment a slot forthe reception of the blade of a slot screwdriver (not shown here), butcan also be constructed as hexagon socket or something similar accordingto the case of application.

Further embodiments of the base screw (7) are to be seen in FIG. 5.While the joining cap screw (8) has always been designed in the same waythe base thread (7) can be altered according to the case of application.FIG. 5 shows different sizes and dimensions (19, 20, 21) of aright-handed metric thread. These special embodiment of the base thread(7) are only examples. For an expert it is obvious that the base thread(7) can have every known thread design, in particular the embodiment ofa base thread (7) with a dowel and a wood screw is possible, too.

Beside the base screw (4) these is also shown in FIG. 3 the inner andexterior structure of the secondary screw (5) shown in longitudinalsection which mainly consists of a reception cap (13) and a right-handedsecondary thread (15). The secondary screw (5) is provided with one ormore slots (16) preferably extending from the reception cap (13) to apin (17) the secondary screw (5) being preferably slotted twice in sucha way that the plan view shows a cross shape. This makes an expansionpossible so that the secondary screw (5) can be moved over the lockingsection (11) of the base screw (4). The pin (17) is located at the endof the secondary screw (5) opposite to the reception cap (13), has acylindrical shape and a shorter diameter than the second thread (15). Inthe interior the secondary screw (5) behind a projection (14) isdesigned in such a way that the inner contour of the reception cap (13)corresponds to the exterior contour of the locking section (11) of thebase screw (4).

The clamping nut (5) of FIG. 4 externally shows in its preferredembodiment the contour of a commercial hexagon nut. The inner contour(18) of the clamping nut (6) is designed in such a way that itcorresponds to the exterior contour of the reception cap (13) of thesecondary screw (5) to permit reception, wherein in a preferredembodiment the exterior contour of the reception cap (13) and the innercontour (18) of the clamping nut (6) are square. Additionally the innercontour (18) of the clamping nut (6) has an additional recess for thereception of the stop (9) of the base screw (4) in assembled condition.

While this inner contour (18) of the clamping nut (6) is always the samein the different designs of the rosette (6) shown in FIG. 7 the exteriorcontour of the clamping nut (5) may have various shapes and dimensions.The designs of a round rosette (22), an ornament rosette (23), and adistance rosette (24) in FIG. 6 are shown as examples only.

The assemblage of two component parts or objects (2, 3) by means of theinvented connecting element (1) with thread on both sides is carried outstep by step in the following way.

Before the assemblage the two objects (2, 33 are provided withright-handed thread bottom holes at the suitable places. Then the basescrew (4) is screwed up to the stop (9) into one of the two objects 2,3). The stop (9) must sit on the thread borehole with its total bearingsurface dimensioned adequately to be in a position to fulfill the taskof a commercial screw head.

After than the secondary screw (5) is put upon the base screw (4) insuch a way that the locking section (11) of the base screw (4) locksbehind the projections (14j in the reception cap (13) of the secondaryscrew (5). Therein the e.g. secondary screw is expanded; this means thatthe four segments of the secondary screw connected for example by thepin (17) and formed by the slot or slots are spread apart. After thelocking of the locking section (11) behind the projections (14) theexpanded segments of the secondary screw (5) return. The function of thepin (17) is for reduction of the cross-section at the end of the secondscrew (5) in order to facilitate the expansion of the segments or tomake it possible even depending on the material of the secondary screw(5).

After there has been created such a positive connection of the secondaryscrew (5) and the base screw (4), the clamping nut (6) is put onto thesecondary screw (5) in such a way that the reception cap (13) and theinner contour (18) of the clamping nut (6) also form a positiveconnection. Thereby the clamping nut (6) is aligned in such a way thatit also covers the stop (9) of the base screw (4) with its inner contour(18). The connecting element according to the invention is now connectedas shown in FIG. 2 the right-handed base screw (4) being located asdescribed above in a right-handed thread bottom hole in a first object(2).

By turning the clamping nut (6) one thereupon screws the right-handedsecondary screw (5) into a likewise right-handed thread bottom hole of asecond object (3) and namely as long that between the locking section(11) of the base screw (4) and the inner contour in the reception cap(13) of the secondary screw (5) there has been obtained a frictionalconnection.

Also smaller alignment defects of the thread bottom hole borings in thetwo component parts of objects (2, 3) can be compensated by the adequatedesign of the joining cap screw (8) and the inner contour of thereception cap (13). Additionally the space between the two objects (2,3) needed for the assembly is reduced from the total length of acommercial connecting element to a little more than half of theconnecting element (1) according to the invention.

The disassembly of the two component parts or objects (2, 3) is carriedout in the reverse manner to the above-described sequence. Therein thedisassembling of base screw (4) and secondary screw (5) is for exampleexecuted after an external expansion of the individual segments. Thesecondary screw (5) may however also be cut off so that the separationof base screw (4) and secondary screw (5) takes place after the fractureof one or several segments of the secondary screw (5).

What is claimed:
 1. A connecting element having opposing first andsecond threaded segments for the detachable connection of two objects,the threads being of the same handed direction, comprising:a firstthreaded segment having a plurality of threads and a joining cap screwlocated at opposing ends of the first threaded segment, the joining capscrew comprising a locking section; a second threaded segment having aplurality of threads and a reception cap located at opposing ends of thesecond threaded segment, the reception cap being turnably received inthe locking section; and a clamping nut having a central bore extendingtherethrough including means for receiving a portion of the secondthreaded segment therein such that the clamping nut can be slid axiallyonto the portion of the second threaded segment whereby, when theclamping nut is slid axially onto the portion of the second threadedsegment, the clamping nut and the second threaded segment are lockablyengaged and rotation of the clamping nut causes rotation of the secondthreaded segment.
 2. A connecting element according to claim 1characterized in that the second threaded segment comprises adjacentprojections separated by a longitudinal slot extending along a length ofthe second threaded segment, the adjacent projections being movablerelative to one another to permit said reception cap to receive saidlocking section.
 3. A connecting element according to claim 2characterized in that the first threaded segment comprises a joining capscrew for connection with the second threaded segment.
 4. A connectingelement according to claim 3 characterized in that the joining cap screwcomprises a stop and a distance section, and the locking section isprovided with a recess for the reception of a screw turning device.
 5. Aconnecting element according to claim 4 characterized in that thelocking section is formed as a truncated cone and is located at athread-free end of the first threaded segment.
 6. A connecting elementaccording to claim 2 characterized in that the reception cap has aninclined surface to facilitate reception of the reception cap in thelocking section.
 7. A connecting element according to claim 6characterized in that the volume enclosed by the reception cap isexpandable by means of a plurality of projections defined by one or morecruciately arranged slots extending a length of the second threadedsegment.
 8. A connecting element according to claim 6 characterized inthat an inner contour of the reception cap is stepped to engage anexterior contour of the locking section located behind a projection ofthe first threaded segment.
 9. A connecting element according to claim 1characterized in that a pin is located at an end of the second threadedsegment, the pin having a cross-sectional area normal to a longitudinalaxis of the second threaded segment that is less than a cross-sectionalarea of an adjacent portion of the second threaded segment normal to thelongitudinal axis.
 10. A connecting element according to claim 4characterized in that an inner contour of the clamping nut is shaped insuch a way that, after assembling the first and second threaded segmentsand clamping nut, there is a positive connection of the clamping nut andan exterior contour of the reception cap of the second threaded segment,and the stop of the first threaded segment is covered by the clampingnut.
 11. A connecting element according to claim 10 characterized inthat the clamping nut is designed as a rosette.
 12. The connectionelement of claim 1, characterized in that, when the clamping nutlockably engages the portion of the second threaded segment, rotation ofthe clamping nut causes rotation of the second threaded segment whilethe first threaded segment is free of rotation.
 13. The connectionelement of claim 1, characterized in that, when the first and secondthreaded segments are turnably engaged, turning of the second threadedsegment relative to the first threaded segment is free of axialdisplacement of the second threaded segment relative to the firstthreaded segment.
 14. A connecting element having opposing first andsecond threaded segments for the detachable connection of two objects,comprising:a first threaded segment having a plurality of threadslocated at an end thereof; a second threaded segment having a pluralityof threads located at an end thereof, the plurality of threads of thefirst threaded segment having the same handed direction as the pluralityof threads of the second threaded segment; connection means forrotatably engaging the first threaded segment to the second threadedsegment, whereby the first and second threaded segments have freedom ofrotation relative to one another, such that rotation of the secondthreaded segment relative to the first threaded segment is free of axialdisplacement of the second threaded segment relative to the firstthreaded segment, the connection means comprising a plurality ofprojections extending from one of the first and second threadedsegments, the plurality of projections being separated by at least onelongitudinal slot extending a substantial length of the one of the firstand second threaded segments and being displaceable relative to oneanother, and a second projection on the other of the first and secondthreaded segments, the second projection being received between theplurality of projections; and a clamping nut for tightening at least oneof the first and second threaded segments in a threaded hole, theclamping nut having a central bore extending therethrough and includingmeans for receiving at least a portion of the at least one of the firstand second threaded segments therein such that the clamping nut can beslid axially onto the at least one of the first and second threadedsegments and, when the clamping nut is slid axially onto the portion ofthe at least one of the first and second threaded segments, the clampingnut and the at least one of the first and second threaded segments arelockably engaged.
 15. The connection element of claim 14, wherein theplurality of projections and second projection define interlocking maleand female portions of the first and second threaded segments.
 16. Theconnection element of claim 14, wherein the first threaded segmentcomprises a stop that abuts ends of the plurality of projections. 17.The connection element of claim 14, wherein the connection meanscomprises an inclined surface on at least one of the first and secondthreaded segments at an end thereof to facilitate rotatable engagementof the first and second threaded segments.
 18. A method for connectingtwo objects to one another, comprising:screwing a first threaded segmentinto a first threaded hole; thereafter rotatably engaging an end of asecond threaded segment with a free end of the first threaded segmentsuch that rotation of the second threaded segment relative to the firstthreaded segment is free of axial displacement of the second threadedsegment relative to the first threaded segment; axially sliding, overthe engaged ends of the first and second threaded segments, a clampingnut for tightening at least one of the first and second threadedsegments, whereby rotation of the clamping nut causes rotation of the atleast one of the first and second threaded segments; and after therotatably engaging step, screwing the second threaded segment into asecond threaded hole having a common longitudinal axis with the firstthreaded hole.